Added HTTPHeaders

Author: michalpokusa

adafruit_httpserver/headers.py

@@ -0,0 +1,100 @@
+# SPDX-FileCopyrightText: Copyright (c) 2022 Dan Halbert for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+"""
+`adafruit_httpserver.headers.HTTPHeaders`
+====================================================
+* Author(s): Michał Pokusa
+"""
+
+try:
+    from typing import Dict, Tuple
+except ImportError:
+    pass
+
+
+class HTTPHeaders:
+    """
+    A dict-like object for storing HTTP headers.
+
+    Allows access to headers using **case insensitive** names.
+
+    Does **not** implement all dict methods.
+
+    Examples::
+
+        headers = HTTPHeaders({"Content-Type": "text/html", "Content-Length": "1024"})
+
+        len(headers)
+        # 2
+
+        headers.setdefault("Access-Control-Allow-Origin", "*")
+        headers["Access-Control-Allow-Origin"]
+        # '*'
+
+        headers["Content-Length"]
+        # '1024'
+
+        headers["content-type"]
+        # 'text/html'
+
+        "CONTENT-TYPE" in headers
+        # True
+    """
+
+    _storage: Dict[str, Tuple[str, str]]
+
+    def __init__(self, headers: Dict[str, str] = None) -> None:
+
+        headers = headers or {}
+
+        self._storage = {key.lower(): [key, value] for key, value in headers.items()}
+
+    def get(self, name: str, default: str = None):
+        """Returns the value for the given header name, or default if not found."""
+        return self._storage.get(name.lower(), [None, default])[1]
+
+    def setdefault(self, name: str, default: str = None):
+        """Sets the value for the given header name if it does not exist."""
+        return self._storage.setdefault(name.lower(), [name, default])[1]
+
+    def items(self):
+        """Returns a list of (name, value) tuples."""
+        return dict(self._storage.values()).items()
+
+    def keys(self):
+        """Returns a list of header names."""
+        return dict(self._storage.values()).keys()
+
+    def values(self):
+        """Returns a list of header values."""
+        return dict(self._storage.values()).values()
+
+    def update(self, headers: Dict[str, str]):
+        """Updates the headers with the given dict."""
+        return self._storage.update({key.lower(): [key, value] for key, value in headers.items()})
+
+    def copy(self):
+        """Returns a copy of the headers."""
+        return HTTPHeaders(dict(self._storage.values()))
+
+    def __getitem__(self, name: str):
+        return self._storage[name.lower()][1]
+
+    def __setitem__(self, name: str, value: str):
+        self._storage[name.lower()] = [name, value]
+
+    def __delitem__(self, name: str):
+        del self._storage[name.lower()]
+
+    def __iter__(self):
+        return iter(dict(self._storage.values()))
+
+    def __len__(self):
+        return len(self._storage)
+
+    def __contains__(self, key: str):
+        return key.lower() in self._storage.keys()
+
+    def __repr__(self):
+        return f'{self.__class__.__name__}({dict(self._storage.values())})'